Sometimes, non-volatile memories are shipped to customers with pre-stored data. A customer may put the memory into another external process, such as a high-temperature process. The high-temperature process may be, for example, a solder bonding process. During such a process, part or all of the pre-stored data in the memory may be lost. For example, a phase-change memory (PCM) stores digital data using different states of a phase-change material, which has different resistances at different states. That is, a phase-change material may have a first resistance when it is in an initial state. When heated to a crystallizing temperature, the phase-change material switches to a polycrystalline state and has a second resistance. Further, when heated to a melting temperature, the phase-change material switches to an amorphous state and has a third resistance. Usually, the polycrystalline state and the amorphous state of a phase-change material are used to represent binary “1” and binary “0”, respectively. Therefore, if a PCM having pre-stored data is subject to a high-temperature process, such as the solder bonding process, the high temperature may cause some or all memory cells of the PCM to change state, resulting in loss of the pre-stored data.